


Kuroo's Body Swapping Juice

by Brilan_Mosyn



Series: Adventures of the Fortress & the Land and Sky [4]
Category: Haikyuu!!
Genre: A little, Crack, I swear, Kuroo Tetsurou is a Little Shit, One Shot, Teen rating for a little bit of foul language, The Title makes sense in context, definitely appropriate for the situation lol
Language: English
Status: Completed
Published: 2020-09-29
Updated: 2020-09-29
Packaged: 2021-03-07 19:07:49
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,672
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26712682
Author URL: https://archiveofourown.org/users/Brilan_Mosyn/pseuds/Brilan_Mosyn
Summary: Hinata and Iwaizumi use Kuroo's body swapping concoction to prank their boyfriends.
Relationships: Hinata Shouyou & Iwaizumi Hajime, Hinata Shouyou/Kageyama Tobio, Iwaizumi Hajime/Oikawa Tooru, Kageyama Tobio & Oikawa Tooru
Series: Adventures of the Fortress & the Land and Sky [4]
Series URL: https://archiveofourown.org/series/1806472
Comments: 2
Kudos: 15





	Kuroo's Body Swapping Juice

**Author's Note:**

> A gazzilion thanks to [Catastra_Fey](https://archiveofourown.org/users/Catastra_Fey) for helping me brainstorm this stuff.

Rap, rap, rap. A heavy knock sounds at the door to Kuroo’s lab.

“Kuroo-san! I brought him!”

Kuroo looks up from where he’s skewering hot dogs and grins at the bouncing redhead and his companion. “Thank you Chibi-chan. Sit down. I’ll have the weiners ready in a few”

Iwaizumi and Hinata sit around Kuroo’s favorite bunsen burner. 

“So why am I here?” Iwaizumi asks after Kuroo has passed the skewers around.

“Shorty and I thought you could help us with something.”

“And that would be?”

Kuroo smirks. “We want you to help us prank Oikawa and

Kageyama.”

Iwaizumi scratches the top of his head, suddenly reminded of the last time the materials for a Kuroo prank ended up on the Fortress.

“Oh? What do you have in mind?”

“This,” Kuroo responds, bringing out two glass bottles. “This my friend, Kuroo’s Body Swap Juice. When these two bottles here are drunk the two people ingesting will swap bodies for a total of 24 hours.”

“I see what you’re thinking. And how would this work?”

“Let’s see… You and Kageyama should switch. It’ll be easier that way.”

Iwaizumi bursts out laughing. “I like it. Tonight, Hinata?”

The redhead nods. “Works for me.”

Kuroo spears another hot dog. “It only activates when both parties are asleep, so you can drink it at any time tonight.”

Hinata and Iwaizumi leave a few minutes later, bottles of Kuroo’s concoction stuffed into their pockets.

“See you later, Hinata?”

“Yup.”

Just before bedtime, Iwaizumi sits in bed, body swap juice in one hand and his texting device in the other. 

**Hinata Shouyou: Milk spiked and drunk. Waiting for Bakageyama to go to sleep. You?**

Iwaizumi takes a deep breath before downing the bottle and tossing it into the trash. 

**Me: Downed. Now we wait.**

Oikawa slips into bed. “What’s wrong, Iwa-chan? You’ve been acting so weird since Chibi-chan called you over to the Land and Sky.”

Iwaizumi suppresses a flinch, hoping the beat of his heart doesn’t betray him. “Hmmm. Just tired.” 

“Are you sure?”

“I’m sure. Now go to sleep.”

_ Tomorrow is going to be a long day, _ he thinks.

“Hmph. Whatever.”

Oikawa tucks himself under Iwaizumi’s arm, easily falling into a deep sleep.

Oikawa’s soft snores eases his nervousness, pulling him into dreamland.

Beeeep, beeeeep, beeeep. A blaring alarm drags Kageyama out of a dreamless sleep and into a hazy state of partial-lucidity. Even in his half-awake state, he can’t help but sense something off.

“Iwa-chan, Iwa-chan. Wake up you sleepyhead!”

An unusually large hand whacks his shoulder. The weight of the impact is enough to chase away the last of the haze.

Kageyama blinks twice, then looks up to find Oikawa straddling him, glaring at him.

“What’s gotten into you, Iwa-chan? First you’re all mopey. Now you sleep in longer than me. I don’t have to resort to extreme measures, do I?”

Kageyama’s heart races. Oikawa’s voice is too sweet, his eyes holding too much mischief, but he can’t but ask, “H-how would you do that?”

“Hmmm. You ought to know by now, Hajime. And here I thought we were over our communication issues.”

_ But I’m not Iwaizumi-san! This isn’t even my room! _ Tobio thinks in an ever growing panic.

Oikawa leans forward to press a blazing kiss on his lips. 

Kageyama jerks back, pushing the elder man away. “NO! I’m not Iwaizumi-san!”

Oikawa’s look grows dark. “What the fuck? If you’re not Hajime, who are you.”

Kageyama gulps, but answers, “Ka-kageyama.”

  
  


Oikawa’s first reaction when Kageyama speaks his name is rage. How dare Tobio-chan take his Iwa-chan’s place! 

His second is far calmer. Everyone knows that Kageyama isn’t smart enough to pull something like this off, and he’s incapable of lying about it.

Kageyama glances up from the broad hands he’s been so carefully studying. “You-you’re not mad?”

For the first time in his life, Oikawa feels sympathy for the younger man. Although not happy about Iwaizumi being replaced by Kageyama, he still wears his own face.

“I am. I’m pissed but not at you. You’re not smart enough to be at fault and I’ve never seen you lie successfully. This leaves a few options. A) Iwa-chan picked up a disease yesterday--no. That’s not it. You’re dating Chibi-chan, right?”

“Yeah. What of it?”

“Was he acting weird yesterday.”

Kageyama lowers his head, eyes narrowed in thought. Eventually, he nods. “He was, a little. He’s always excited so I didn’t think much of it.”

“You rarely do, but that’s not the point. If Chibi-chan and Iwa-chan wanted to prank us, who would they go to?”

“Kuroo-san. He’s supposed to be the king of all pranks.”

Oikawa sniffs. “Of course it would be Tetsu-chan. Get dressed, Tobio-chan! We’re going to go interrogate an dumb cat.”

Kageyama hurries to put on the clothes Oikawa tossed to him, only to trip and fall face first onto the ground.

Oikawa quickly joins him, brought to his knees by uncontrollable laughter. “You--you,” the researcher gasps through his tears, “This is the best.”

“You’re mean,” Kageyama mutters, still working on getting Iwaizumi’s limbs in working order.

“Hurry up, Tobio-chan. I want my Iwa-chan back.”

“I’m trying!”

Oikawa helps Kageyama to his feet, only to have him trip again.

“Fine! This isn’t working. Get on my back. If anyone asks, you’re too sick to speak and it’s Kuroo Tetsurou’s fault.”

Back on the Land and Sky, Hinata and Iwaizumi sit on Hinata’s bed, holding a controller and screen for one of Kenma’s tiny drones.

“How long do you think it will be before they come over?”

Iwaizumi glances at the clock. “No more than 10 minutes. Tooru is going to be pissed.”

“I’m a dead man, aren’t I?”

“Both of us are. Kuroo more so, though.”

“Why?”

“He started it. Shhh. Look.”

Iwaizumi points to the screen. A tiny Oikawa walks on screen, carrying “Iwaizumi” on his back.

“I’m hitting the record button,” Hinata laughs, hitting a small red button. “This is worth the death sentence.”

“It might be,” Iwaizumi snorts. “It’s certainly blackmail material.”

The pair turn their attention back to the screen, watching as the pranked duo descends to the science department.

“Do we have audio on this?”

“Ummmm. Kenma said to press the yellow and green buttons at the same time for sound.”

Iwaizumi does then settles back.

_ “How are you holding up, Tobio-chan?” _

_ “I’m being carried around by you.” _

_ Oikawa gasps. “Rude, Tobio-chan. You should be glad I’m giving you a piggy back ride.” _

“In what world is Oikawa Tooru even close to nice to Kageyama?” Hinata asks.”

“One where Kuroo is Public Enemy #1. Are we warning Kuroo?”

“Nah. He’s a big boy.”

“You’re a cruel person, Hinata.”

“Am not. Kuroo-san is probably expecting the two.”

“Fair enough.”

_ Oikawa and Kageyama walk into the science section’s containment zone. _

_ “Where’s Kuroo,” Oikawa demands. _

_ Tsukishima points in a random direction. “I told him it was a bad idea,” the blond mutters just loud enough for the drone to pick up before going back to his notetaking. _

_ Finally, the pair reaches Kuroo’s lab and busts in. “Kuroo Tetsurou!” _

_ The scientist in question looks up, wearing one of his self satisfied smirks. “So what can I do for you gentlemen?” _

_ “Fix this! I want my Iwa-chan back.” _

_ Oikawa’s whine is pathetic, paired with a matching pout and puppy dog eyes. _

_ Kuroo raises his eyes to look directly at the mini drone. _

“I guess that’s our cue. Can you walk, Iwaizumi-san?”

Iwaizumi stands and stretches. He’s unsteady, but unlike Kageyama, he has more coordination than a newborn calf. “I had time to practice, remember?”

“Heh. Right.”

Hinata and Iwaizumi hurry down, returning the drone to Kenma in the process.

“It’s about time,” Oikawa hisses when the two enter the lab.

Hinata shrugs. “It took us a little to get down here.”

The researcher turns back to Kuroo. “Fucking fix it.”

“Hmm. It should wear off in 24 hours. But if you’re absolutely sure, there is an antidote. It hasn’t been tested yet, so it could just make it worse.”

The other four share a look.

Hinata glares at the science section’s chief. “You didn’t tell me you were using us as test subjects.”

“I thought it would be obvious, Chibi.”

“Let’s do the antidote. 24 hours is a lot.” Oikawa says with an air of finality.

“If you say so,” Kuroo responds, reaching behind him to grab another pair of vials. 

Iwaizumi and Kageyama take the vials and drink the contents, both praying that Kuroo really is a genius and that the antidote works.

A few seconds later, the two sprawled on the floor, back in their original bodies. 

Hinata and Oikawa reach out to their respective boyfriends, only to find no hands to be taken. Both Iwaizumi and Kageyama have shrunk to no longer than 6 inches tall.

“Kuroo!”

Hinata and Oikawa turn on the scientist who has busied himself digging through his notes.

“I’ll fix it, I’ll fix it!”

“You’d better,” Oikawa says, malice dripping from his words.

“If you don’t I’ll set Kenma on you.” Hinata adds.

“I wouldn’t be opposed to doing that anyway.”

“Or we could just beat him up.”

“Your captain would object.”

“Probably. I have it!”

“What Chibi-chan? What have you thought of?”

Hinata rises on his toes to whisper in Oikawa’s ear. 

“I love it.”

Kuroo goes pale, but finally pulls out the reference sheet he's looking for.

He rushes into the back, scanning the shelves for a mix he uses when experiments like this go horribly wrong.

“Found it!”

Kuroo comes back out with a vial and a dropper. “One experiment reversal solution coming right up.”

Two hours later, all humans are in their proper bodies. 

Hinata and Oikawa grin at Kuroo, leaving a bud of fear growing in his gut. 

“What do you plan to do to me?”

“Just make you watch reruns of Aka-chan the Orange Alien,” Oikawa tells him. “All. Day. Long.”

Kuroo sinks to the floor.  _ Maybe facing the wrath of Kenma doesn’t sound so bad after all. _

**Author's Note:**

> That was fun. Thank you guys for the reads.
> 
> I'm at [Haikyuu Haven](https://discord.com/invite/qpPHkdw) if anyobne wants to chatter.


End file.
